In cutting inserts, particularly cutting inserts for grooving process, it becomes important to reduce damage to a machined surface due to generated chips. For example, patent document 1 discloses a cutting insert for grooving process including a cutting edge having a concave part in a midportion thereof, a concave groove which is provided continuously with the concave part of the cutting edge, and has a flat bottom surface, and an inclined surface disposed behind the concave groove. Chips generated by this cutting insert are compressed in the width direction thereof by the concave groove of the cutting insert, and the width of the chips becomes smaller than a cutting edge width. Therefore, the chips are less likely to come into contact with the machined surface, thereby reducing damage to the machined surface due to the chips.